I like a plant that comes up every year. Annuals can be very striking, but I personally enjoy a hardy plant or tree that has a firm place in the garden, a home. I would rather have a full garden of different shapes, sizes and textures than a bunch of continuous tiny flowers.
Probably because it is a 'safer' growth form to follow; relying on seeds every year can be risky. Also, it is likely the basal state in Angiosperms - the earliest-separated groups of Angiospems are all perennial, and mostly woody (Amborellaceae: shrub, Nymphaeaceae: herbaceous perennials, Austrobaileyaceae: woody vines, Schisandraceae: trees, shrubs).
To add to what Michael F. said 1. Many plants grown as annuals in Canada, grow as perennials in their (warmer) areas of origin. 2. Perennials can employ a wide variety of reproductive strategies both sexual & asexual to ensure their survival...think of how bulbs, corms, cones, nuts...etc.etc. survive our cold winters. 3. Size. If you live multiple years, you can outgrow smaller annual competitors & store biomass to bring to reproductive efforts. Confers advantages in several other ways I can think of as well. 4. Earlier growth in a short growing season. That stored biomass can be deployed to start earlier than competitors (Check-out my namesake - the Skunk Cabbage - Lysichiton, which has it's own built-in heating system) Just some ideas. BTW this would make a great exam essay question for some course, eh?
hmm, interesting points. does this mean, evolutionarily speaking, that perennials have dominant traits (ie. more adaptable, smaller, stronger, etc) and would hypothetically win in the process of natural selection? is it possible that annuals will eventually become extinct or do they have specific traits that make them crucial to the planet's sustainability? also - why would a plant grow as an annual in canada but a perennial in their hometown? from what you've said it seems perennials can better survive colder climates? hope my questions aren't foolish.. i'm still a noob when it comes to understanding ma nature.
Broadly speaking, the annual growth form works exceptionally well in ecological conditions where disturbance of some sort -- soil perturbation, temperature extremes (particularly hot), spring flooding (or pools) with temporary anaerobic conditions -- is an annual event.
nibs9, I was thinking of garden plants when I said about the plants here that are annuals, but are perennials in warmer climes. Of course a lot of these jsut don't produce viable seed & are sold afresh each year (e.g. Pelargoniums, Fuschias, Basil ). I am not sure if there any native plants that are annuals here & perennials elswhere. Hmm? Another interesting line of thought...Daniel?
I would guess plenty some, but one I was able to find quickly is the blue-listed Persicaria punctata, which is treated in the Illustrated Flora of BC as being an annual, but is described in Flora of North America as being annual or perennial -- I'm guessing likely a perennial in places like Florida and Texas.
